1. Field of the Invention
The present invention relates to a head substrate provided with recording execution means for executing recording according to recording data and memory means for storing various data, a printing head utilizing such head substrate, and a printing apparatus utilizing such printing head.
2. Related Background Art
There are already commercialized various printing apparatuses, including such an apparatus having a replaceable printing head as an ink jet printer. As an example, in the ink jet printer, plural external connection terminals are provided in a printer main body and a printing head, and these terminals are mutually connected when the printing head is mounted on the printer main body.
In such state, the printer main body can transfer various signals such as a recording image signal and a recording clock signal to the printing head, so that the printing head can execute the recording of the externally entered image signal at a timing corresponding to the recording clock signal.
In such printer apparatus with the replaceable printing head, it is now proposed to provide a printing head with various data such as ID (identification) data of the head in readable manner. For this purpose, it is proposed to provide a printing head with data memory means such as ROM (read only memory), as disclosed in the Japanese Patent Application Laid-Open Nos. 3-126560 and 8-177732 and the U.S. Pat. Nos. 5,504,507 and 5,363,134.
This type of printing head can be interchangeable mounted on the printer main body and can also store various data by the data memory means in arbitrarily readable manner.
However, in case the printing head is provided with the data memory means such as ROM, it is necessary to provide the printing head and the printer main body with exclusive plural connection terminals for executing the access to the memory. Such configuration increases the dimension of the external connection terminals in the printing head and in the printer main body, with a loss in the productivity thereof.
Also in case various signals are used commonly for the recording operation and the data writing/reading in/from the memory, data may be written by a noise generated in the course of the recording operation. In such case, the stored data are overwritten by the noise so that an error is generated in the data readout.